General description
β-Galactose Dehydrogenase plays a crucial role in galactose metabolism by catalyzing the pyridine-nucleotide-dependent dehydrogenation of β-D-galactopyranose to yield NADH and D-galactono-l,5-1actone. D-galactose dehydrogenase from P. fluorescens is a member of the oxidoreductases family. It is composed of two identical subunits and has a molecular weight of 64,000. Additionally, the enzyme contains two binding sites.
Application
β-Galactose Dehydrogenase has been used as a reporter enzyme in neuraminidase (NA) kinetic parameters for the natural substrates 6′-Sialyl-N-acetyllactosamine (6SLN) and 3′-Sialyl-N-acetyllactosamine (3SLN).
Biochem/physiol Actions
Galactose dehydrogenase will oxidize D-galactose [Km = 0.7 mM (30 °C, pH 9.1); relative rate = 1.00], L-arabinose (relative rate = 0.47), D-fucose (relative rate = 1.05), 2-deoxy-D-galactose (relative rate = 0.27), 2-amino-2-deoxy-D-galactose [galactosamine], (relative rate = 0.02; pH 8.6).
Galactose dehydrogenase does not oxidize L-galactose, D-arabinose, D-glucose, L-fucose, D-ribose, D-xylose, D-glucuronic acid, D-galacturonic acid or D-galactose-6-phosphate. The enzyme will use either NAD (Km = 0.24 mM; relative rate = 1.0) or NADP (Km = 2.3 mM; relative rate = 0.32).
Physical form
Suspension in 3.2 M ammonium sulfate solution, 1 mM EDTA, pH approximately 6
Analysis Note
Contaminants: <0.01% ADH, <0.01% ?-galactosidase, <0.1% NADH oxidase, <0.5% LDH
Other Notes
For life science research only. Not for use in diagnostic procedures.
Galactose dehydrogenase from Pseudomonas fluorescens (MW 64,000 D) is a dimer with subunits of equal size (subunit MW = 32,000 D).
One unit galactose dehydrogenase will oxidize 1 mol of β-D-galactose in one minute at +25 °C and pH 8.6.
The QC assay produces 1 mol of NADH per mol of galactose oxidized.
| biological source | Pseudomonas fluorescens |
| recombinant | expressed in E. coli |
| form | suspension |
| specific activity | ~5 units/mg protein (At 25 °C with D-galactose as the substrate; standardized with BSA.) |
| mol wt | 64,000 Da |
| packaging | pkg of 1 mL (10104973001 [1 mg]),pkg of 1 mL (10104981001 [5 mg]) |
| manufacturer/tradename | Roche |
| technique(s) | activity assay: suitable |
| color | white |
| optimum pH | 8.4 (0.1 M in Tris buffer) |
| pH range | 4.6-9.2 |
| solubility | water: soluble |
| suitability | suitable for enzyme test |
| UniProt accession no. | (T1WEA6 · T1WEA6_PSEFL) |
| foreign activity | ADH <0.01%,LDH <0.5%,NADH oxidase <0.1%,galactosidase <0.01% |
| storage temp. | 2-8°C |
